that determined L2 later learners' ultimate achievement, but it has less effect on L2 early learners. John B. Carroll John B. Carroll, an influential psychologist in the field of educational linguistics, developed a theory about a cluster of four abilities that factored into language learning aptitude, separate from verbal intelligence and motivation. Using these four distinct abilities (phonetic coding ability, grammatical sensitivity, rote learning ability, and inductive learning ability), Carroll developed the MLAT, a language aptitude assessment for adults. The four ability components are defined as follows: Paul Pimsleur Paul Pimsleur, also known for the Pimsleur language learning system, spent time researching four factors that he believed to be related to language learning aptitude. Pimsleur included grade point average as an indication of general academic achievement as well as motivation in his factors. In addition, the verbal ability factor indicated how well a student would be able to handle the mechanics of learning a foreign language and the auditory factor indicated how well a student would be able to listen to and produce phrases in a foreign language. To test these four factors, Pimsleur developed the Pimsleur Language Aptitude Battery, which is available through the Language Learning and Testing Foundation. Uses of aptitude measurement Measurements of language learning aptitude are used in many different ways. The United States Department of Defense uses a measurement of language learning aptitude, the Defense Language Aptitude Battery, to help place employees in positions that require them to learn a new language. Governmental agencies use the MLAT as a tool to select and place employees in intensive language training programs. Businesses and missionaries use the MLAT to select, place and plan for language training. Universities, colleges and high schools use the MLAT to help in the diagnosis of foreign language learning disabilities. Although each institution has its own policy, many will waive a foreign language requirement in cases of a foreign language learning disability in favor of a history or linguistic course. Schools use the PLAB and MLAT-E to place students in suitable language courses, build a history of a foreign language learning difficulty, identify especially gifted students in respect to language learning and to match learning styles with instructional styles. Aptitude tests See also Aptitude Hardest language References Resources Carroll, John B. and Stanley Sapon. Modern Language Aptitude Test: Manual 2002 Edition. Rockville, MD: Language Learning and Testing Foundation, 2002. Carroll, John B. and